Due to increasing environmental pollutions of water resources more people are relying on water dispensers at home and work places to provide drinking water. Sale of water dispensers has increased rapidly. Water dispensers are well known in the art for containing a supply of purified water and commonly include an upwardly open water reservoir mounted within a cooler housing or cabinet adapted to receive and support an inverted water bottle of typically three to five gallon capacity. The water within the bottle flows downward into the water reservoir, and depending upon the design, one or more taps dispense water to the user.
Although bottled water is cleaned and purified by the water bottle company, often the water dispenser is operated for months without proper disinfection maintenance. Bacteria in air can get into the dispenser machine and grow inside. Usually there are recommended instructions for cleaning the water dispenser to disinfect it periodically. However, the cleaning process is time consuming and may involve taking apart the system with special tools and may sometimes require chemical(s) in order to kill the microbial. Rinses are often required to get rid of such chemical residue and the smell introduced during the cleaning process. Due to the above reasons, most users tend to neglect these recommended cleanings until serious health problem occurs.
Inherent in the current water dispenser design are problems associated with sterility. To address the sanitizing problem, a liquid dispenser with a better hygienic adapter that is easier to take apart has been invented as described by U.S. Pat. No. 6,123,232. However, that invention does not address the many hard to reach internal surfaces associated with the plumbing of the dispenser machine, where bacteria can reside. U.S. Pat. No. 20050087554A1 describes a method and apparatus for disinfecting a refrigerated water cooler reservoir by generating ozone for sanitizing the water. However, since the bottle water has already been processed with ozone, repeating the same process inside a water dispenser for the purpose of sanitizing the machine is not economical. Furthermore, it is the machine that needs to be sterilized not the water. It is better to have a sterilizing system that is simple, effective and economical. PCT publication WO 01/52909 A1 describes a method and device for sanitizing bottled water dispensers using an external steam generator. However, there is a wide variety of water dispensers each with a different internal design; a typical modern dispenser with hygienic design often prevents the user from seeing the water remaining inside the water reservoir. A direct injection of steam without knowledge about the water left inside the dispenser machine may cause serious injury. Another potential problem that has not been considered by patent application WO 01/52909 A1 is that an advanced water dispenser machine using electric valves to dispense water cannot be turned off while disinfecting the machine. The refrigeration thus can turn on automatically upon introducing hot steam into the machine, directly interfering with the disinfection process. In addition the sterilization would not be thorough due to many internal surfaces and pockets still covered by residual water, as well as cold spots due to refrigeration; the external device is not only cumbersome, but also not economical and not suitable for performing a complete and safe disinfection process. Furthermore, the methods described by patent application WO 01/52909 A1 omitted the critical step of emptying the remaining water in the system before introducing the pressurized steam into the flow path. Its methods, therefore, are not sufficient to ensure a safe operation.
Considering the users may consist of a wide spectrum of age and intelligence, a better and safer water dispenser with disinfection capability is needed. In other words, a modern water dispenser machine should include sensors that indicate the readiness of the machine for performing the sterilization procedure, as well as monitoring the completeness of the process. In addition, the present invention installs a mechanical safety valve on the sealing cover to prevent accident due to a malfunction of the water dispenser machine and its sterilization.
Hot steam is also widely used in commercial products. It is technologically feasible to integrate a steam generator with a water dispenser machine. In fact, it is better and safer to invent a new water dispenser machine appropriate for steam sterilization rather than trying to adapt this new technology to existing water dispensers that are not designed for steam disinfection. However, it is challenging to invent a water dispenser machine having steam sterilization capability, without significantly altering its original designs and functions in order to keep the production cost at its minimum. An invention that includes this new health improvement technology, yet still providing customers with an easy and safer operation and leaving them with the various choices of different water dispenser, is essential to the market.